Seeds have been treated with a wide variety of enhancement chemicals and other materials for decades. The recent development of transgenic crops has resulted in an increased focus on seed treatment, because of the increased value of such genetically-modified seeds.
Both continuous and batch seed treaters are known to the art. Most continuous treaters are industrial scale and are designed to efficiently treat relatively large seed lots (i.e., thousands of pounds of seed). Smaller seed lots have traditionally been treated using laboratory batch treaters. Spinning disc treaters like the Hege 11, are popular and utilize different size dressing bowls to treat seed batch sizes from 20 grams up to 3000 grams. The liquid seed dressing dose is delivered to the rotating seed using a syringe barrel or other dispensing device. Rotating pots, drums or pans are effective to treat small seed batches ranging from 25 grams to several 100 lbs. The liquid seed dressing is typically atomized onto the rotating seed surface or delivered by a drip tube. Automizing or misting the liquid seed dressing onto seed can result in off target spray. Misting applies a liquid seed dressing gradually. The coating is built up over time while the seed continuously tumbles. Heavier seed kernels like corn, can begin to rub off the coating as seed to seed contact causes coating abrasion. This technique can become counter productive as the process proceeds. Seed dressing equipment, particularly dressing implements that are not disposable such as atomization nozzles, pots, dressing containers, ventillated enclousures, etc. which become contaminated during the application process must be thoroughly cleaned before a different liquid seed dressing is applied. For small seed lots this can become laborious, time consuming and highly variable depending on the operators experience level. For seed lots of less than 20 grams, comprised of only a few kernels of seed, for example, 10-40 seeds—there are no suitable, exacting reproducible treatment methods. The dilemma of applying a liquid seed dressing to only a few kernels can be delicate and awkward for a treater.
These small seed lots, such as genetically-modified seeds, are often extremely valuable. Examples of these small seed lots include parent seeds (e.g., breeders, foundation, registered), hand-produced hybrid seeds, and vegetable seeds. These small seed lots must be treated uniformly with fungicides, insecticides and other materials to eliminate losses from diseases, insects and harsh conditions. Oftentimes these small seed lots are treated by shaking the seeds in a jar performed by laboratory personnel. The inner walls of the jar can be coated with as much liquid seed dressing as the seeds themselves resulting in non-uniform and inconsistent application of the liquid seed dressing dose. Every individual is different and the implements and conditions in which they apply liquid seed dressing to small seed lots can vary greatly in practice. In addition, laboratory personnel may experience ergonomic trauma to their wrists as a result of hand shaking large numbers of seed lots over time. Unwanted residual chemical carryover between high value seed lots must be eliminated. Heretofore, systems for the treatment of small seed lots have used inefficient protocols and equipment which have failed to eliminate carryover. Accordingly, these protocols and equipment often resulted in seed lots, which were not treated uniformly and/or were contaminated with carryover seed and/or treatment materials.
Dry application seed treatment formulations are dusty and can present unacceptable worker exposure to air borne and particulate active ingredients. Liquid systems, particularly those that are aqueous based are preferred. Certain liquid formulations can become inhomogeneous on storage, such that particle size or viscosity do not remain constant. Additional problems can arise such as unacceptable drying times, material build-up in the seed treater, low seed flowability, poor seed coverage and dust-off of the active ingredient from the seed prior to planting. As a result, handling is rendered difficult and the biological efficacy and integrity of the seed treatment is reduced.
Uniformity of application is particularly important when testing new active ingredients. Currently available treaters often require relatively large amounts of active ingredients for application to the seeds. This becomes an issue when the new active ingredients have a high economic value on a per gram basis and supply is limited. Currently available treaters present challenges in testing these new active ingredients over a range of active ingredient doses applied to multiple seed types in order to determine their optimal dosages and seed response. Thus, uniformity of application is particularly important when testing new active ingredients.
Accordingly, there is then a need for seed treatment methods that eliminate contamination from carryover seed and/or treatment materials in small seed lots and provide uniformly covered seeds having high biological efficacy post planting. There is also a need for protocols and equipment that are user friendly, easy to load and treat with, which allow operators to focus on other attributes of the seed treatment besides the application process.